We find this circuit in an Electronics Now. The indication of the logic level is done on a 7-segment display according to the connections given in the diagram.
We found this simple alarm circuit in a 1986 documentation. The circuit uses sensors of the NA...
This sound relay or Vox was found in 70s RCA documentation. SCRs can be common types today and...
Placed near a common receiver, this oscillator is intended to generate a beating signal to receive...